Adam,
We reuse concentrators but only for the same protein. (i.e. don't
cross-contaminate) I believe we got a protocol from the centricon manual
or the Amicon catalog. At any rate we soak the filter units in 70 %
ethanol and never let them dry. Just before reusing them we rinse them
and spin with the same buffer in which our protein is solubilized. (i.e.
PBS) Then we load on the new protein and spin. Hope this helps. It seems
to work fine for us.
Matthew L. Brown, Ph.D.
Dept. of Medicine
Univ. of Alabama at Birmingham
P.S. I know you from Steve's lab I think...